if (document.images) {

  onhome=new Image
  offhome=new Image

  onsearch=new Image
  offsearch=new Image

  onnewsearch=new Image
  offnewsearch=new Image
 
 

  onhome.src="http://www.shoppingtrolley.net/buttons/home1.gif"
  offhome.src="http://www.shoppingtrolley.net/buttons/home2.gif"
 
  onsearch.src="http://www.shoppingtrolley.net/buttons/search1.gif"
  offsearch.src="http://www.shoppingtrolley.net/buttons/search2.gif"

  onnewsearch.src="images/search1.gif"
  offnewsearch.src="images/search.gif"
 

}

function chgImg(imgfield,newImg) {
  if (document.images) {
     document[imgfield].src=eval(newImg+".src")
  }
}